Insecticides: Types, Advantages, Disadvantages

Insecticides are chemicals that are used to control insects either by killing them or by stopping them from participating in undesired or damaging activity. Insecticides have several applications in health, agriculture, and industry. Insects pose a significant hazard to crops because they can destroy plant leaves, roots, and stems, turning them unsuitable for food or other uses and perhaps damaging the plants. For the best crop protection against these pests—some of which only feed on specific crops—insecticides must be used.

What are Insecticides?

The term “insecticide” refers to chemicals that kill insects.

Insecticide, any toxic substance that is used to kill insects. They are employed in agriculture to manage pests that infest farmed crops, but they also have other applications, such as eradicating insects that transfer illnesses. They have the ability to significantly change ecosystem components and are hazardous to both animals and humans. A pesticide is an insecticide. These two words are interchangeable.

Types of Insecticides

Insecticides can be classed in a variety of ways, including how they function, their mode of action, and what they’re comprised of.

Based on Chemical Composition

Inorganics

Most famous four inorganic insecticides: arsenic, soap, boric acid, and diatomaceous earth. Arsenic is an old toxin that was used to eliminate chewing pests on plants. Because arsenic is hazardous to people, it is no longer widely employed as an insecticide.

Soap insecticides are made from the same fatty acid soaps that we use to wash with. They are widely sprayed on plant-eating insects and must come into touch with the insects while still wet in order to be effective. Soaps most likely kill insects by damaging the nervous system (paralysis) and breaking the insect’s waterproof waxy covering on the exterior. This implies the animal will ultimately lose all of its internal moisture and die as a result of dehydration.

Organic gardeners frequently utilize diatomaceous earth as a soil supplement. This insecticide is derived from minerals collected from soil containing dead diatoms from ancient lake or ocean bottoms. A diatom is a form of algae that can survive inside the skeleton of a solidified silicate. Silicon is quite abrasive and, like boric acid and soaps, tears away the waxy coating. It can destroy a wide range of pests, but it must be used under very particular conditions. It works well in dry environments and is widely used in preserved products such as pasta and grains.

Botanicals

Pyrethrum, nicotine, rotenones, and neem extracts are examples of botanical insecticides. Pyrethrum has long been used and is derived from a flower comparable to the common chrysanthemum. It has some interesting qualities since it swiftly knocks insects down. If you spray pyrethrum in the air at a fly, it will fall to the ground in a fraction of a second. It is not dangerous to other animals or people. For these reasons, it is frequently used to treat home pet pests. When pyrethrum is combined with other synergistic substances, it becomes far more deadly than when used alone.

Based on Activity

Insecticides are broadly classified into two types:

Systemic insecticides

These are the insecticides that become a part of the plant by systematic dispersion. Insects that feed on it ingest the pesticide plants and are killed. Systemic insecticides have residual or long-term action.

Contact insecticides

Insecticides that can penetrate the skin of the insects are included. When insects come into touch with them, they become poisonous. They can be of several types, including naturally occurring and manufactured organic substances. In general, contact insecticides have little or no residual action.

The following are some of the most common contact insecticides:
Asana: This is another type of leaf spray used to combat numerous pests. It may be exceedingly hazardous to aquatic species if it gets into rivers. It is suitable for corn, sweet potatoes, cucurbits, maize, herbs, and roots.

Aztec: Excellent against corn rootworms, white grubs, seedcorn beetles, and cutworms. It is a pyrethroid-organophosphate combination that may be put to sweet corn and popcorn with Baythroid:

Brigade: A pyrethroid insecticide used to kill flea beetles, aphids, leafhoppers, caterpillars, and a variety of other insects. It is frequently used as a foliar mist on all types of food crops, although it is especially hazardous to fish and bees.

Captiva: It is a more natural kind of contact insecticide manufactured from plant extracts. It is a leaf spray that is effective on all types of food and vegetable plants. It aids in the eradication of all types of insects and their larvae.

Declare: This pesticide is used to get rid of numerous types of insects. It is extremely dangerous to bees and aquatic creatures. It may be applied on crops including sweet corn, onions, cabbage, and tuberous vegetables.

Rotenone

Rotenone is derived from tropical plants and was initially used to kill fish by indigenous peoples. It is still used in this manner today (when a fisheries project wishes to rid a body of water of undesired fish), but it is also used as a spray or dust to control chewing insects in garden and fruit crops.

The seeds of neem plants prevalent in tropical climates are used to extract neem oil. It is gaining popularity since, unlike DDT, it degrades swiftly in the environment and is harmless for animals.

Based on Toxicity

Extremely toxic – Color: red, symbol: skull and poison, oral LD50: 1-50
Moderately hazardous – blue color, caution sign, oral LD50: 501 – 5000

Highly poisonous – yellow color, poison symbol, oral LD50: 51 – 500

Less hazardous – Green color, caution sign, oral LD50: >5000

The stage of particularity. This pesticide is divided into four categories: ovicides, pupicides, larvicides, and adulticides.

Types of Synthetic Insecticides

Synthetic insecticides are the most widely used form of pesticide. They can be poisonous to a broad variety of insect species. Among the most common forms of synthetic pesticides are:

Chlorinated Hydrocarbons

These insecticides, also known as organochlorines, chlorinated organics, chlorinated insecticides, and chlorinated synthetics, contain carbon, chlorine, and hydrogen. Some of these pesticides had long-lasting residual effects and were effective for extended periods of time. They were invented in the 1940s but have since become obsolete.

Organophosphates

These are phosphorus-containing insecticides produced from one of the phosphorous acids. Organophosphates are efficient in controlling insect populations because they impede the nervous system’s function. They work particularly well against sucking insects that feed on plant liquids. Because they have low residual activity, they have become quite popular in usage because they may fulfill the residual tolerance restrictions that may be in place for crop productivity.

Carbamates

Carbamates are insecticides made from carbamic acid. They are excellent at repelling insects, but they can also be swiftly detoxified from mammalian tissues, making them less hazardous to both animals and humans.

There are several commercially available pesticides. All pesticides come with instructions on how to use them so that they can control insects and prevent crop damage without being dangerous to people.

Advantages of Insecticides

  • Insecticides can boost yields, increasing output and revenue: They are a simple and effective method of managing insect populations that might otherwise cause agricultural harm. Without insecticides, huge percentages of cultivated crops would be wasted, resulting in a loss of income for farmers as well as a waste of the resources required to produce the crops. It is possible to increase yields by using pesticides.
  • Insecticides boost crop quality: Consumers want pest-free fruits and vegetables, and pesticides have a direct role in ensuring crop quality is not compromised by insects. Controlling insects also reduces some plant illnesses carried by insects, which can lead to quality degradation.
  • Insecticides boost crop quality: Consumers want pest-free fruits and vegetables, and pesticides have a direct role in ensuring crop quality is not compromised by insects. Controlling insects also reduces some plant illnesses carried by insects, which can lead to quality degradation.
  • Insecticides can provide effective pest control in a short period of time: Insecticides allow pests to be controlled fast. Even when there is a large population of destructive bugs, pesticides may usually be employed to decrease the pests within hours.
  • Insecticides can give protection against a wide range of insect species: Some pesticides give broad-spectrum protection, and others can be applied in conjunction with one another to control many pest species at the same time. Insecticides are continually being produced in order to give protection against new pest species.

Disadvantages of Insecticides

  • Influences food quality: Toxic chemical residues may be detected in food crops. These substances may be incorporated into food, causing significant and major health concerns in both humans and animals.
  • Poisoning risk: Insecticides damage all living things. Humans will experience nausea, headaches, discomfort, and major poisoning issues as a result of the usage of pesticides in agriculture.
  • Responsible pollutants: Pesticides are very deadly air, soil, and water poisons.
  • Impact on the food chain: Another organism may ingest the pesticide that is in the insect’s body, resulting in biomagnification. At greater tropic levels, massive populations of species are impacted.
  • Loss of useful insects: Insecticides not only kill the intended hazardous insects, but they also kill the beneficial insects that fertilize them. As a result, the life cycle of plants is significantly impacted.

References

  • Aktar, Md. Wasim, Dwaipayan Sengupta, and Ashim Chowdhury. “Impact of Pesticides Use in Agriculture: Their Benefits and Hazards.” Interdisciplinary Toxicology 2.1 (2009): 1-12. PMC.
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  • https://www.chefsbest.com/advantages-disadvantages-pesticides/
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  • https://www.impehcm.org.vn/content/news-events/common-types-of-insecticides.html
  • Arias-Estévez, Manuel, et al. “The Mobility and Degradation of Pesticides in Soils and the Pollution of Groundwater Resources.” Agriculture, Ecosystems & Environment 123.4 (2008): 247-260.
  • Cooper, Jerry and Dobson, Hans. “The Benefits of Pesticides to Mankind and the Environment.” Crop Protection 26 (2007): 1337-1348.
  • https://www.cantol.com/resources/types-of-insecticides/
  • https://www.upl-ltd.com/agricultural-solutions/crop-protection/insecticides
  • Corsini, E., et al. “Pesticide Induced Immunotoxicity in Humans: A Comprehensive Review of the Existing Evidence.” Toxicology 307 (2013): 123-135.
  • https://byjus.com/chemistry/insecticides/

About Author

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Kabita Sharma

Kabita Sharma is a graduate student from the central department of chemistry, Tribhuvan University. She has been actively involved in research related to natural products, computational chemistry, and nanochemistry. She is currently working on enzyme assay, molecular docking, and molecular dynamic simulation.

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